TOPIC:

I've had a 1981 GPz550 for about 25 years now. She has been sitting for a long time, and I discovered a few years ago that the rear master cylinder is toast (rusted, frozen).

The problem is that Kawasaki used that master cylinder for (I think) only that model and only that year, so there are no rebuild kits and NOS parts don't exist. I asked here on KZR a while back about ways to work around this, and someone (sadly I forget who it was) mentioned using a Ninja 250 part with minor adaptation. That sounded like a good idea, but with other projects the GPz stayed on the back burner.

Then a couple nights ago I happened to search an auction site for "Kawasaki GPz550" - didn't mention a year or anything... lo and behold, there was a listing for a rear master cylinder for a 1981 GPz550. A more detailed search revealed that it was the only such part available on the site at the time.

It will be here Friday. I'm looking forward to getting the 550 back on the road sooner than later.

Good luck. That is indeed only used on that one particular year and model so there are no rebuild parts available. But after buying several used ones over the years, I realize a rebuild kit is no longer really enough to get an old neglected one working even if you could get a kit.

I am also the one who mentioned the Ninja 250 with slight mods. I can repost it if you end up needing to go that route. There was just nothing I could do to get the pitting out of the old neglected masters so they always ended up leaking a bit. I still have two that have been in continuous use probably since 1981 with fluid changes etc, and they still work fine. But any that sit on a shelf or on a bike in the weather, are usually toast.

I've got that exact same master on my KZ750E. Only difference between the 750E master and GPz part is the color. And it took me several purchases before finding a master that didn't have pitting in the metal bore. I got lucky to find a clean one and hope you do the same. If not, I'd do what loudvx suggests and get a newer master and adapt it.

That was you! Thanks, Lou.

Here is a pic of the item:



It seems to be in pretty good shape and is described as having no leaks and being pulled from a bike with ~30k miles. I'll give it a closer look this weekend but I'm cautiously optimistic.

Cheers!

Thanks, Ed. I'll have my fingers crossed that it's in good condition.

You can always have it re-sleeved...

The part actually arrived today. Woohoo!

I haven't gotten to open it yet. D'oh!


Edit: I unwrapped it today (Friday) and the piston moves freely and smoothly. Whew! If time permits I'll get a better look at it this weekend.

I rebuildef mine rear master cylinder, find all parts on partzilla.

gordone wrote: I rebuildef mine rear master cylinder, find all parts on partzilla.

Unfortunately a lot of the parts are no longer available, even at Partzilla. Have a look: www.partzilla.com/catalog/kawasaki/motor...rear-master-cylinder

But something interesting happened. After looking at Partzilla, I had the part number for the piston assembly. I took a chance and searched eBay again, just in case I might have good luck...

And I found a new old stock (NOS) piston assembly in Canada! It should arrive here around the end of the month.



Once again it was the only such item available on the site. The universe must want me to get the GPz back on the road. I won't argue.

If you nneed one more rear master Piston

japan.webike.net/products/21727563.html

Fits KAWASAKI Z400FX (E4) 82-83
Corresponding OEM Parts No.: 43020-1022/43067-001/43058-004/43024-003

Ausgezeichnet - vielen Dank!